[ELF] -r: don't parse @ (symbol versioning) for .symver inline asm in bitcode

[MaskRay]

Summary

Fixes PR46420
Similar to D43307 for non-LTO.

Module-level inline assembly can use .symver to create a symbol with @ in the name.
For relocatable output, @ should be retained in the symbol name. @ver should
not be parsed and dropped.

[MaskRay]

Fix a comment and improve test

[nextsilicon-itay-bookstein]

Used the exact same fix as a local workaround until further counsel on the bug report, so looks good to me.
Thank you!

[psmith]

Looks good to me. Agree that symbol versioning should be passed through in a relocatable link.

[grimar]

Looks reasonable. You don't need SHNDX I think.

lld/test/ELF/lto/version-script2.ll

3–5

Test -> test

14

This defines SHNDX which is never used I think. Why just you didn't use a section index instead?

[MaskRay]

Address comments

[MaskRay]

lld/test/ELF/lto/version-script2.ll

14

The variable name cannot be omitted:

% cat a.txt
CHECK: [[#%u:]]
% FileCheck a.txt
a.txt:1:11: error: invalid variable name
CHECK: [[#%u:]]
          ^

I'll use {{ instead.

lld/ELF/Driver.cpp

template <class ELFT> void LinkerDriver::compileBitcodeFiles() {
   // Compile bitcode files and replace bitcode symbols.
   lto.reset(new BitcodeCompiler);
   for (BitcodeFile *file : bitcodeFiles)
     lto->add(*file);
 
   for (InputFile *file : lto->compile()) {
     auto *obj = cast<ObjFile<ELFT>>(file);
     obj->parse(/*ignoreComdats=*/true);
+
+    // Parse '@' in symbol names for non-relocatable output.
+    if (!config->relocatable)
       for (Symbol *sym : obj->getGlobalSymbols())
         sym->parseSymbolVersion();
     objectFiles.push_back(file);
   }
 }
 
 // The --wrap option is a feature to rename symbols so that you can write
 // wrappers for existing functions. If you pass `-wrap=foo`, all
 // occurrences of symbol `foo` are resolved to `wrap_foo` (so, you are
 // expected to write `wrap_foo` function as a wrapper). The original

lld/test/ELF/lto/version-script2.ll

 ; REQUIRES: x86
 
-;; Test we parse symbol versions before LTO, otherwise we may get a symbol
-;; named "foo@@VER1", but not "foo" with the version VER1.
+;; For non-relocatable output, test we parse symbol versions after LTO,
+;; otherwise we may get a symbol named "foo@@VER1", but not "foo" with the
+;; version VER1.
 
 ; RUN: llvm-as %s -o %t.o
 ; RUN: echo "VER1 {};" > %t.script
 ; RUN: ld.lld %t.o -o %t.so -shared --version-script %t.script
-; RUN: llvm-readobj --dyn-syms %t.so | FileCheck %s
+; RUN: llvm-readelf --dyn-syms %t.so | FileCheck %s
 
-; CHECK: Name: foo@@VER1 (
+;; For non-relocatable output, @ in symbol names has no effect on undefined symbols.
+; CHECK:      UND       bar{{$}}
+; CHECK-NEXT: {{[1-9]}} foo@@VER1
+
+;; For relocatable output, @ should be retained in the symbol name.
+;; Don't parse and drop `@VER1`. Also check that --version-script is ignored.
+; RUN: ld.lld %t.o -o %t.ro -r --version-script %t.script
+; RUN: llvm-readelf -s %t.ro | FileCheck %s --check-prefix=RELOCATABLE
+
+; RELOCATABLE:      {{[1-9]}} foo@@VER1
+; RELOCATABLE-NEXT: UND       bar@VER1
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 module asm ".global foo"
-module asm "foo:"
+module asm "foo: call bar"
 module asm ".symver foo,foo@@@VER1"
+module asm ".symver bar,bar@@@VER1"